As for playoffs, I think 6 is actually the best number. I'm not convinced a 7th or 8th team really has a claim to compete for the playoffs at the end of the season.
If it is 6, it allows for the 5 P5 conference champs (not that there would be an autobid), and a wildcard. But of course if one of the conferences is weak and their champ just is ranked low and out of the top 6, then that opens up another slot.
Treat the format like the NFL conference playoffs. Top two get a bye, and it goes from there. Use the big bowls as rotating regional sites - unless Rose continues to be fucks. Just leave them out at that point. They can get Big 10/Pac 12 leftovers every season.
But Orange, Fiesta, Sugar, Cotton, and Peach can all be in the mix to rotate the regional games and host the championship.